• Journal of Institute of Control, Robotics and Systems
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• v.11 no.7
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• pp.633-643
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• 2005

An unmanned aerial vehicle (UAV) is an aircraft controlled by .emote commands from ground station and/o. pre-programmed onboard autopilot system. A navigation system in the UAV provides a navigation data for a flight control computer(FCC). The FCC requires accurate and reliable position, velocity and attitude information for guidance and control. This paper proposes an ADGPS/INS integrated navigation system for a UAV. The proposed navigation system comprises an attitude determination GPS (ADGPS) receive., a navigation computer unit, and a low-cost commercial MEMS inertial measurement unit(IMU). The navigation algorithm contains a fault detection and isolation (FDI) function fur integrity. In order to evaluate the performance of the proposed navigation system, two flight tests were preformed using a small aircraft. The first flight test was carried out to confirm fundamental operation of the proposed navigation system and to check the effectiveness of the FDI algorithm. In the second flight test, the navigation performance and the benefit of the GPS attitude information were checked in a high dynamic environment. The flight test results show that the proposed ADGPS/INS integrated navigation system gives a reliable performance even when anomalous GPS data is provided and better navigation performance than a conventional GPS/INS integration unit.

• Journal of Astronomy and Space Sciences
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• v.35 no.3
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• pp.163-173
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• 2018

This paper presents relative navigation using intermittent laser-based measurement data for spacecraft flying formation that consist of two spacecrafts; namely, chief and deputy spacecrafts. The measurement data consists of the relative distance measured by a femtosecond laser, and the relative angles between the two spacecrafts. The filtering algorithms used for the relative navigation are the extended Kalman filter (EKF), unscented Kalman filter (UKF), and least squares recursive filter (LSRF). Numerical simulations reveal that the relative navigation performances of the EKF- and UKF-based relative navigation algorithms decrease in accuracy as the measurement outage period increases. However, the relative navigation performance of the UKF-based algorithm is 95 % more accurate than that of the EKF-based algorithm when the measurement outage period is 80 sec. Although the relative navigation performance of the LSRF-based relative navigation algorithm is 94 % and 370 % less accurate than those of the EKF- and UKF-based navigation algorithms, respectively, when the measurement outage period is 5 sec; the navigation error varies within a range of 4 %, even though the measurement outage period is increased. The results of this study can be applied to the design of a relative navigation strategy using the developed algorithms with laser-based measurements for spacecraft formation flying.

• The Journal of Korea Robotics Society
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• v.4 no.3
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• pp.169-176
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• 2009

Low-cost sensors have been widely used for mobile robot navigation in recent years. However, navigation performance based on low-cost sensors is not good enough to be practically used. Among many navigation techniques, building of an accurate map is a fundamental task for service robots, and mapping with low-cost IR sensors was investigated in this research. The robot's orientation uncertainty was considered for mapping by modifying the Bayesian update formula. Then, the data association scheme was investigated to improve the quality of a built map when the robot's pose uncertainty was large. Six low-cost IR sensors mounted on the robot could not give rich data enough to align the range data by the scan matching method, so a new sample-based method was proposed for data association. The real experiments indicated that the mapping method proposed in this research was able to generate a useful map for navigation.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.7-8
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• 2010

Due to development of wireless environment and portable device, it is possible to use navigation out of car. Specially, pedestrians can freely walk openspace, so there are limits that we use network data of car navigation systems for pedestrian navigation systems. Therefore, in this paper, we proposed the method of generating network data for pedestrians based on the exiting spatial data sets.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.115-116
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• 2017

In this paper, we propose a standardization strategy for next generation electronic navigational chart which can be classified as S-100 Universal Hydrographic Data Model, to accept various requirements arising from various marine information and services as well as support e-navigation service strategies. IMO uses the next generation electronic chart standard, S-100 as Common Maritime Data Structure. It means that a common data model is needed as a key element for realization of e-Navigation and also points out that a new ICT convergence paradigm is needed not only for marine safety but also for maritime information and services. this paper considers he model-based data representation and reference model in order to understand the content and use of the S-100 standard and also considers the interconnectivity and role of the ISO/TC211 standards, which are being used as base standards for profiling to develop S-100 standard. Finally, we look at what standardization items are required for standardization of next generation electronic navigational chart supporting multi-purpose and how they are used mutually.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.337-342
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• 2006

The use of GPS receiver at outer space becomes common in low earth orbit. The KOrea Multi-Purpose SATellite-1 (KOMPSAT-1) which was launched in December 1999 has used GPS receiver's navigation solution to perform the Orbit Determination (OD) in the ground. At the circumstance of using only one ground station, the Orbit Determination using GPS receiver is good method. Because the accuracy of navigation solution acquiring directly from GPS receiver is not enough in satellite application such as map generation, post-processing concepts such as the Precise Orbit Determination (POD) are applied to satellite data processing to improve satellite position accuracy. The POD uses GPS receiver's raw measurement data instead of GPS receiver's navigation solution. The KOrea Multi- Purpose SATellite-2 (KOMPSAT-2) system newly uses the POD technique for large scale map generation. The satellite was launched in the end of July 2006. The satellite sends high resolution images in panchromatic band and multi-spectral bands to the ground. The satellite system uses GPS receivers as source of time synchronization and command reference in the satellite, provider of navigation solution for the OD, and provider of raw measurement data for the POD. In this paper, mechanical configuration and operations of the GPS receiver will be presented. The GPS data characteristics of the satellite such as time synchronization, command reference, the OD using GPS receiver's navigation solution, and the POD using GPS receiver's raw measurement data will be presented and analyzed. The enhancement of performance compared with it of the previous satellite will also be analyzed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.22-24
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• 2017

The Korean e-Navigation operating system is designed to provide various services related to marine safety. These services are not configured to be provided in one software, but are made in separate software. In order to integrate the service software installed in the e-Navigation operating system, it is necessary to define the data message which can exchange data between the service software, Depending on the operating concept of the service, many messages are expected to be transmitted over the network in a short time. There is a need for a buffer or message queue to store messages as a way to manage messages efficiently. Therefore, in this paper, we analyze the types and characteristics of Advanced Message Queuing Protocol(AMQP) suitable for Korean e-Navigation operating system and shows that's result.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.44-45
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• 2022

The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) has been developing the S-201 Aids to Navigation information standard since 2019 for the purpose of exchanging Aids to Navigation data. In this study, the navigation information managed in Korea was modeled using the IALA S-201 navigation information standard system for the management and service of smart navigation. By using the S-201 Aids to Navigation information standard system, the basis for reflecting the information standard system was prepared in the production, exchange, and collection of domestic navigational data. It also intends to contribute to the establishment of an information exchange system between the Aids to Navigation organization, IALA, and countries.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.211-211
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• 2017

• Journal of Positioning, Navigation, and Timing
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• v.3 no.3
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• pp.99-105
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• 2014

A graphic processing unit (GPU) can perform the same calculation on multiple data (SIMD: single instruction multiple data) using hundreds of to thousands of special purpose processors for graphic processing. Thus, high efficiency is expected when GPU is used for the generation and correlation of satellite navigation signals, which perform generation and processing by applying the same calculation procedure to tens of millions of discrete signal samples per second. In this study, the structure of a GPU-based GNSS simulator for the generation and processing of satellite navigation signals was designed, developed, and verified. To verify the developed satellite navigation signal generator, generated signals were applied to the OEM-V3 receiver of Novatel Inc., and the measured values were examined. To verify the satellite navigation signal processor, the performance was examined by collecting and processing actual GNSS intermediate frequency signals. The results of the verification indicated that satellite navigation signals could be generated and processed in real time using two GPUs.